Slide valves are known in many constructions in the art. They are distinguished in that smaller forces are required for actuating the valve side than in what are known as seat valves, in which a valve element cooperates with a valve seat. The lower forces in a slide valve basically result from the fact that the slide is adjusted perpendicular to the flow direction of the controlled fluid, and therefore, ignoring friction, the pressure of the controlled fluid has a much smaller effect on the required adjusting force.
A problem with conventional slide valves is that the valve drive used generally consumes energy even when stationary. For example, the coil of an electromagnetic valve drive has to be excited continuously during the operation of the slide valve so as to hold the slide in the desired position.
A further problem which occurs in slide valves is the required installation space. In particular, if there is an electromagnetic drive, it is scarcely possible to make it more compact.
Very recently, attempts have also been made at using piezoelectric valve drives. However, drives of this type are very complex (for example because of a required stroke transmission) if they are able to produce a sufficiently large adjustment distance, such as is required for a slide valve.
The object of the invention is to provide a slide valve by means of which a fluid or a plurality of fluids can be controlled with direct electrical actuation, at minimal energy consumption, with as little pressure loss as possible. Further, it should be possible to adjust the slide proportionally without the valve drive consuming energy when stationary.